Traditional telephony devices utilize dual-tone multi-frequency (“DTMF”) signaling (also referred to as touch-tone dialing) to establish telephone call connections and perform other functions after a connection is established. With DTMF, each key or digit that is pressed on a telephone generates two tones of specific frequencies. These tones are pulse code modulated and transmitted by way of a public-switched telephone network (“PSTN”) to a receiving telephony device. The receiving telephony device may then demodulate the received pulse code modulated tones to determine which keys were pressed.
However, with the advent of the Internet, voice communications are increasingly being transported over IP networks such as the Internet and other packet-switched networks. To this end, numerous types of Voice over Internet Protocol (“VoIP”) telephony devices have been developed that are configured to transmit and receive packet-based communications instead of DTMF tones. For example, many VoIP telephony devices are configured to send and receive packet-based representations of digits that have been encoded in accordance with a standard known as RFC2833.
To facilitate communication between traditional analog telephony devices and VoIP telephony devices, one or more gateway devices may be provided that translate DTMF tones into packet-based representations and vice versa. For example, DTMF tones representative of a digit sequence that are generated by an analog telephony device may be routed through a gateway device, which translates the DTMF tones into a packet-based representation of the digit sequence that may be received by a VoIP telephony device. The gateway device may similarly translate a packet-based representation of a digit sequence into DTMF tones that may be received by an analog telephony device.
It has been found that some gateway devices do not accurately translate DTMF tones into packet-based representations and vice versa. For example, some gateway devices do not function properly when deployed within a network environment associated with a particular service provider. Hence, it is often desirable to test gateway devices before they are deployed.